Thread carrier for sewing machine loop taker



Aug. 23, 1960 L. J. KUHAR 2,949,874

THREAD CARRIER FOR SEWING MACHINE LOOP TAKER Filed Sept. 1s, 1.958

INVENTOR. Ludwig J. Kuhar BY W ATTORNEY WITNESS Fi 5 g United THREAD CARRIER FOR SEWING MACHINE LOOP TAKER Filed Sept. 16, 1958, Ser. No. 761,424

2 Claims. (Cl. 112-231) The present invention relates to a thread carrier for the loop taker of a lock stitch sewing machine and particularly to a thread carrier that is designed to accommodate a thread mass in the form of a pre-wound cop, preferably of the center-unwind type, or in other words, a thread mass which is wound upon itself and does not include the conventional bobbin upon which the thread is wound.

The object of this invention is to facilitate the insertion and removal of the thread mass in a thread carrier of a sewing machine loop taker designed to accommodate a pre-wound cop.

Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and arrangements of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it when read in conjunction with the accompanying drawings in which:

Fig. 1 is an elevational view of a rotary hook for a sewing machine having thread carrier means in accordance with this invention.

Fig. 2 is a perspective view of the thread case per se of the rotary hook illustrated in Fig. 1.

Fig. 3 is a perspective view of the thread case carrier per se of the rotary hook illustrated in Fig. 1.

Fig. 4 is a sectional view of the thread case and taken substantially on the line 4-4 of Fig. 1.

Fig. 5 is a fragmentary detail sectional view taken substantially on the line 5-5 of Fig. 3.

There is illustrated in the drawings a sewing machine rotary hook 1 having a hook body 2 in which is journaled the peripheral bearing rib 3 of a thread case carrier 4 for rotation of the hook body 2 relatively to the thread case carrier 4. The thread case carrier 4 includes a bottom wall 5 and a cylindrical side wall 6 upon the periphery of which is formed the bearing rib 3. Mounted within the thread case carrier 4 is a thread case 7 having a top wall 8 and a cylindrical side wall 9. The space within the side wall 9 constitutes the thread mass receiving cavity in which the cop is adapted to be mounted. Being more particularly designed to accommodate a center-unwind pre-wound cop, the thread case 7 is formed centrally of the top wall 8 with a thread aperture 10 through which the thread lead is adapted to pass. A thread tension spring 11 is secured to the side wall 9 of the thread case 7 by a screw 12 and is bent at a right angle to extend across the top wall 8 with the free end overlying the aperture 10. The interior of the side wall 6 of the thread case carrier 4 is provided with a groove 13 to accommodate the screw 12 and the leg of the spring 11 on the periphery of the thread case. The spring 11 includes a thread eye 14 spaced from the aperture 10 through which eye 14 the thread emerges from beneath the tension spring 11. The action of the tension spring 11 can be varied by means of an adjustment screw atent O 15 extending through the spring and threaded into the top wall 8 of the thread case. A threading slot 16 extends through the side wall 9 and top wall 8 from the free edge of the side wall 9 to the thread aperture 10. To prevent insertion of the thread case 7 into the thread case carrier 4 in other than the correct angular relation and also to prevent angular displacement between them, there is provided an inwardly extending stud 17 on the side wall 6 of the thread case carrier that is designed to be received in a wide-mouthed slot 18 in the side wall 9 of the thread case.

The thread case 7 is secured in the thread case carrier 4 by means comprising a latch 19 slidably mounted on the top wall 8 of the thread case 7 in undercut grooves 20 and having the free end 21 thereof disposed to enter in latching position into an aperture 22 in the side wall 6 of the thread case carrier 4. The latch 19 is biased into latching position by a coil spring 23 seated in a bore 24 in the top wall 8 and bearing at its opposite ends against the bottom of the bore and against the laterally extending ear 28 on the latch 19. The latch 19 is retracted from latching position to withdraw the free end 21 thereof from the aperture 22 by a lever 26 pivotally mounted by a pivot pin 27 on the end of the latch 19 opposite from the free end 21 and having a cam arm 28 extending into an aperture 29 in the top wall 8 of the thread case 7. A stop screw 30 is threaded into the latch 19 with the head thereof seated in a slot 31 in the top wall 8.

The spring 23 biases the latch 19 laterally of the thread case 7 into latching position with the free end 21 thereof extending into the aperture 22 in the side wall 6 of the thread case carrier 4. Sliding movement of the latch 19 under the action of the spring 23 is limited by engagement of the cam arm 28 with the end of the aperture 29. To retract the latch 19 and thereby withdraw the end 21 from the aperture 22 to release the thread case 7 from the thread case carrier 4, the lever 26 is pivoted upwardly which with the cam arm 28 in engagement with the end of the aperture 29, forces the latch 19 to move endwise. The stop screw 30 engages the inner end of the slot 31 to limit the amount of movement that can be imparted to the latch 19.

To hold the thread mass in the thread case 7 when the thread case is removed from the machine, there is provided a slot 32 in the side wall 9 of the thread case which slot 32 communicates with the slot 31. Seated in the slot 32 is a pin 33 mounted on the latch 19 at a point inwardly from the free end 21 a distance such that the pin 33 will lie in the slot 32 when the latch 19 is in latching position. When the latch 19 is retracted from latching position, the pin 33 is moved inwardly into the space within the confines of the side wall 9 to engage the periphery of a thread mass in the thread case to force it against the opposite point on the side wall 9 and thus frictionally hold it in the thread case. The pin 33 is elongated so that it will engage a substantial portion of the width of the thread mass to insure adequate engagement of the thread mass.

On the periphery of the thread case carrier 4 above the bearing rib 3, there is mounted a leaf spring 34 that is secured to the thread case carrier 4 at a point intermediate its ends by a screw 35. The opposite ends of the spring 34 are bent inwardly as at 36 and extend through apertures 37 in the side Wall 6 into engagement with the side wall 9 of the thread case 7. The spring 34 acts to place a bias on the thread case 7 thereby preventing relative motion between the thread case and the thread case carrier which would result in rattling during operation of the hook.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a rotary hook for sewing machines, a thread case carrier having a cylindrical side wall, a thread ease removably mounted in said thread case carrier and adapted to receive a thread mass, said thread case having a side wall and a top wall, means for retaining said thread case in said thread case carrier comprising a latch slidably mounted on the top wall of said thread case, the side wall of said thread case carrier having an aperture adapted to be entered by the end of said latch when in latching position, spring means for biasing said latch into latching position, a latch operating lever for retracting said latch from latching position, said thread case having a slot in the side wall thereof, and a pin carried by and spaced inwardly from the end of said latch and seated in said slot when said latch is in latching position and disposed within the confines of the side wall of said thread case when said latch is retracted from latching position for engaging the periphery of and thereby holding a thread mass within said thread case.

2. In a rotary hook for sewing machines, a thread case carrier having a. cylindrical side wall, a thread case removably mounted in said thread case carrier and adapted to receive a thread mass, said thread case having a side wall and a top wall, means comprising a latch slidably mounted on the top wall of said thread case and cooperating with said thread case carrier when in latching position for retaining said thread casein said thread case carrier, spring means for biasing said latch into latching position, a latch operating lever for retracting said latch from latching position, means on said latch for engaging and holding a thread mass in said thread case when said latch is retracted from operative position, the side wall of said thread case carrier having a pair of spaced apertures, and a leaf spring secured to the periphery of said thread case carrier and having the ends thereof bent inwardly and extending through the apertures into engagement with the periphery of the thread case.

References Cited in the file of this patent UNITED STATES PATENTS 1,981,834 Fleckenstein Nov. 20, 1934 2,154,403 Karle Apr. 11, 1939 2,419,698 Wood Apr. 29, 1947 2,802,438 Colegrove Aug. 13, 1957 

